The present invention relates a mold exchanger system for a tire vulcanizing machine.
It is known that vulcanization step in the final stage of tire production has to accommodate frequent change in size or type of tires customarily performed in the preceding production stages. In most cases, it is necessary to exchange a tire vulcanizing mold, which is installed in the vulcanizing machine, with a new mold corresponding to the change in size or type of tires.
The vulcanizing molds are significantly heavy articles and, thus it is not very easy to perform handlings and operations as required for mounting such molds into vulcanizing machines or exchanging the previous mold, which is installed in the vulcanizing machine, with a new mold. This applies to the case where the mold is a split-type mold comprised of two mold halves, though the problem is more serious in a segmented-type mold having a more complex structure than the split-type mold. This is because the segmented-type mold is comprised of a number of mold elements for forming the tire tread portion, which are arranged in the circumferential direction.
Therefore, it is a conventional practice that the previous and new molds are transferred by using a fork lift truck, and the removal of the prior mold from the vulcanizing machine and the installation of the new mold onto the vulcanizing machine are performed by using a hoist or a crane. However, these operations involve a number of problems that labors and significant time are required, the productivity of the vulcanizing process is lowered and works are inevitably done for a long time under a high temperature condition.
Thus, JP-A-5-229,643 discloses a system for exchanging the upper and lower molds relative to a plurality of vulcanizing machines, such as a low pressure foundry machine, aiming at automation and labor-saving. The exchanger system is comprised of a primary carriage that is movable along a guide means in front of the vulcanizing machines, a secondary carriage mounted on the primary carriage and carrying the upper and lower molds thereon, and a connector rotatably provided for the primary carriage, wherein the secondary carriage is movable along the connector as it is connected to a corresponding connector fixedly provided for the vulcanizing machine so that the secondary carriage can be moved onto the base member of the vulcanizing machine.
With the mold exchanger system having such a structure, it is practically impossible for the running surfaces on the primary carriage, the running surfaces of the connectors, and the running surfaces of the plurality of, or a number of vulcanizing machines, to be aligned on the same horizontal plane relative to each other. Misalignment of the running surfaces of these elements occurs inevitably, thereby causing troubles when the heavy upper and lower molds are moved onto the base member or the secondary carriage. Moreover, the mold cannot be positioned on the base member with a sufficient accuracy, and this is a significant problem when tire vulcanizing molds are to be transferred, for which a precise positioning plays a decisive role for realizing high quality products.
JP-A-6-315,938 discloses a mold exchanger system which is comprised of a main carriage that is movable along a number of vulcanizing machines, a slider carriage provided on the main carriage and movable toward the vulcanizing machine, and a turntable provided on the slider carriage, wherein the slider carriage carrying the mold is reciprocatingly moved along rails on the turntable and rails within the vulcanizing machine which are connected to each other by connector rails.
Such a mold exchanger system also involves problems that, in order to cause a reciprocating movement of the slider carriage, it is necessary to provide rails inside of the vulcanizing machine, thereby requiring an extensive modification of the machine. The positioning means also involves a problem that it is the slider carriage, not the mold itself, which is positioned relative to the vulcanizing machine and, hence, an accurate centering cannot be achieved.
JP-A-10-6345 discloses a mold exchanger system wherein the previous mold removed from the vulcanizing machine is returned to a stock site, and a next mold selected at the stock site is installed into the vulcanizing machine. The exchanger system is comprised of upper and lower mold supports forming a pair, an elevating means for the pair of the supports, and a lifter for moving the supports to and from the vulcanizing machine, wherein the supports are moved by the lifter to an exchanging position.
Such an exchanger systems is superior to the former two types in that the existing vulcanizing machines can be used as they are, without requiring modification of the machines, and that the mold can be exchanged smoothly. However, in connection with the precise positioning of the mold itself, it is desirable to improve the system since it is the exchanger system itself which is positioned relative to the vulcanizing machine. It is also desirable to improve the system since the system as a whole has a complicated structure and is thus costly, besides that the exchange of the mold requires a relatively long time.
In any of the prior art system explained above, the function of the system is insufficient when the mold is of segmented-type, wherein it is desired to remove the used mold from the vulcanizing machine easily and quickly, and precisely transfer a next mold to the vulcanizing machine. This is because the segmented mold is comprised of two elements, i.e., a mold main body which is relevant to the vulcanization and profiling of the tire, and a container enclosing the mold main body.
The mold main body is comprised of a number of radially movable mold elements for forming the tire tread portion, an upper side mold portion and a lower side mold portion. On the other hand, the container serves to separate the mold elements by causing them to move radially outwards, and integrating the mold elements by causing them to move radially inwards. Thus, the segmented-type mold has a more complicated structure as compared to the split-type mold, and it is more difficult to achieve a facilitated and precise transfer of the segmented-type mold.
It is therefore a primary object of the present invention to eliminate the above-mentioned problems of the prior art.
It is a more specific object of the present invention to provide a mold exchanger system having a simple structure, which allows a precise centering and positioning of the mold relative to the vulcanizing machine, allows the mold to be transferred to the vulcanizing machine and removed therefrom in a smooth and facilitated manner, and allows improvement in the mold exchanging efficiency by significantly reducing the transfer time and removing time.
To attain the above-mentioned object, according to the present invention, there is provided mold exchanger system comprising a transfer means for transferring into a vulcanizing machine a mold arranged on outside of the vulcanizing machine, and transferring the mold arranged inside of the vulcanizing machine to outside thereof, and a mount for supporting the transfer means, wherein said transfer means comprises a height adjusting means for adjusting the transferring height of the mold, and a positioning means for positioning the mold relative to the vulcanizing machine.
The transfer means in the mold exchanger system according to the present invention may comprise a body that is connected to its mount, a first conveyor fixedly secured to the body, and a second conveyor that can be moved between a position adjacent to the first conveyor on the body and a position inside of the vulcanizing machine. In this instance, transfer means may comprise a movable mould mount plate to be carried by the first and the second conveyors. Also, the transfer means may comprise a drive means for reciprocatingly moving the mold mount plate between said body in the transfer means and inside of the vulcanizing machine.
The height adjusting means in the mold exchanger system according to the present invention may comprise a motor and a jack which can be elevated as it is driven by the drive motor, said jack having a top end which is connected to the body of the transfer means. In this instance, the jack of the height adjusting means may have an elevating stroke that corresponds to the sum of a level difference between the reciprocating movement of the second conveyor and its abutment with a vulcanizing machine, and a difference in mounting height between the molds of a plurality of vulcanizing machines.
The positioning means in the mold exchanger system according to the present invention may comprise a positioning register for the mold, that is arranged at a center in an upper surface of the mold mounting plate, a plurality of notches arranged at side edge locations of the mold mounting plate on the side of the vulcanizing machine, and a plurality of positioning members which are situated on a back side of the vulcanizing machine and engageable with the respective notches.
Alternatively, the positioning means in the mold exchanger system according to the present invention may comprise a positioning register for the mold, that is arranged at a center in an upper surface of the mold mounting plate, a plurality of notches arranged at an outer peripheral surface of mold on the side of the vulcanizing machine, and a plurality of positioning members which are situated on a back side of the vulcanizing machine and engageable with the respective notches.
In any case, the positioning members situated on the back side of the vulcanizing machine may be arranged on the same circumference of a lower holder of the vulcanizing machine.
In the mold exchanger system according to the present invention, it is preferred that two sets of said transfer means are arranged in pair on the same mount, and associated with a distance adjusting mechanism for adjusting a distance of said transfer means relative to each other.
The mold exchanger system constructed as above can be positioned relative to a vulcanizing machine in which two molds are mounted side by side as seem from a front side of the vulcanizing machine. In this instance, the transfer means of the pair may be opposed to each other in a direction in which the two molds of the vulcanizing machine are arranged.
Also, the distance adjusting mechanism may comprise a moving means for reciprocatingly moving at least one of the transfer means in the opposing direction. In this instance, the moving means may comprise a guide means for guiding said movement of said one of the transfer means, and a drive means for moving said one transfer means while being guided by said guide means. Furthermore, the drive means for the transfer means may comprise a ball-screw mechanism having a nut that is fixedly secured to the transfer means, and a motor for driving a male screw of the ball-screw mechanism. Also, the distance adjusting mechanism may comprise a controller for controlling a rotating direction and a rotating speed of said motor based on a data representing the distance between the two molds in the vulcanizing machine and also on a data representing the distance between a center axis position of one of the molds and a reference point of the positioning means.
In the mold exchanger system according to the present invention, the pair of transfer means may each comprise a height adjusting means for adjusting the transfer height of the mold to be mounted. In this instance, the height adjusting means may comprise a motor fixedly arranged on the support, two pairs of corner jacks on the support, that can be driven by the motor and thereby elevated, a frame connected to top ends of elevating portions of the jacks, and a moving means in the distance adjusting mechanism, that is arranged on the frame. The frame of said height adjusting means may comprise sliding members engageable with respective guide members which project vertically from four corners of the support, said sliding members being connected to the top ends of the elevating portions of the jacks.
In the mold exchanger system according to the present invention, the transfer means forming the pair may each comprise a first conveyor fixedly arranged in a direction perpendicular to said opposing direction, and a second conveyor that can be moved between a position adjacent to the first conveyor on the body and a position inside of the vulcanizing machine. In this instance, the transfer means may each comprise a movable mold mount plate to be carried by the first and the second conveyors.
In the mold exchanger system according to the present invention, the transfer means forming the pair may each comprise a mold positioning means for positioning the mold, which is being transferred, in a direction toward inside of the vulcanizing machine. In this instance, the mold positioning means may comprise a notch formed in the mold mount plate and engageable with a positioning member provided at inside of the vulcanizing machine, and a mold centering register provided for the mold mount plate.
In the mold exchanger system according to the present invention, it is preferred that the transfer means comprises a pair of mount portions foe individually mounting two molds which are aligned in the same transfer direction, a transfer mechanism for individually moving the mount portions one by one, in its access position to and from the lower part of the vulcanizing machine, and an elevating means for moving one of the mount portions vertically between said access position level and a higher level.
The elevating means may be arranged such that it is in engagement with said one of the mount portions during its upward movement, and disengaged from said one of the mount portions after completion of its downward movement.
The elevating means may have a vertical stroke such that one of the mount portions carrying a mold can be passed through a lower side of another mount portion which is situated in its higher level.
With reference to the moving mechanism, the transfer means may comprise a first conveyor fixedly arranged with reference to said support, a second conveyor that can be moved between a position adjacent to the first conveyor on the body and a position inside of the vulcanizing machine, and a third conveyor that is arranged behind said first conveyor. In this instance, the third conveyor may have a rotational center at a rear upper side of the transfer means and is rotatable between a lateral position in which it is aligned in the same direction as the first conveyor, and a longitudinal position on the rear side of the transfer means. One of the mount portions may be movable in the transfer direction above the first and second conveyors, with the other of the mount positions movable in the transfer direction above the first and third conveyors. At least one pair of said elevating means may be arranged adjacent to, and on both sides of the first conveyor.
In the mold exchanger system constructed as above, the mount portions may each comprise a mold positioning register. Also, the support of the transfer means is comprised of a movable carriage having the height adjusting means for adjusting the height of the transfer means. The carriage may be arranged so as to support thereon a pair of said transfer means that are arranged adjacent to each other in the moving direction of the carriage.